The lender will use the Trigold and IFonline systems to provide all mortgage intermediaries with mortgage sourcing, application, case tracking and compliance facilities.
In addition, Abbey will take a minority shareholding in the IFonline Group.
Ambrose McGinn, director of retail e-commerce at Abbey National, said: "We have taken a considered look at the market and listened carefully to intermediaries, who have told us they want choice, and do not believe that a single trading platform will be beneficial to them."
"FSA CP98 will require intermediaries and lenders to spend considerable time and money on compliance. IFonline's proposed 'compliance shield solution' will provide a more workable approach to the new regulation."
"We are delighted to be working with the IFonline Group and, together with Abbey National's Introducer Internet system, we will provide the most dynamic front to back-end compliant processing system in the market."
Martin Finegold, chief executive of the IFonline Group, said: "Abbey National's intermediary expertise is clearly demonstrated with the £5 billion worth of agreements-in-principle it received in the first 12 months of its Introducer Internet site. Trigold has leading edge technology solutions to satisfy the requirements of intermediaries, offering them flexible sales and compliance solutions both on and offline."
There are now more than 70 lenders in the Group, which is seeking to serve all intermediaries and customers in the market.
